Phonograph

Edison cylinder phonograph from about 1899 The phonograph, or gramophone, was the most common device for playing recorded sound from the 1870s through the 1980s. Usage of these terms is somewhat different in American English and British English; see usage note below. In more modern usage, this device is often called a turntable or record player. In the late 19th and early 20th century, the alternative term talking machine was sometimes used. The phonograph was the first device for recording and replaying sound. The term phonograph meaning "writing sound", is derived from Greek roots. Similar related terms gramophone and graphophone have similar root meanings. The coinage, particularly the use of the "-graph" root, may have been influenced by the then-existing words "phonographic" and "phonography," which referred to a system of phonetic shorthand; in 1852 the New York Times carried an advertisement for "Professor Webster's phonographic class," and in 1859 the New York State Teachers' Association tabled a motion to "employ a phonographic recorder" to record its meetings. Arguably, any device used to record sound or reproduce recorded sound could be called a type of "phonograph", but in common practice it has come to mean historic technologies of sound recording.

History

The phonautograph

The earliest known invention of a phonographic recording device was the phonautograph, invented by Leon Scott and patented on March 25, 1857. It could transcribe sound to a visible medium, but had no means to play back the sound after it was recorded. The device consisted of a horn that focused sound waves onto a membrane to which a hog's bristle was attached, causing the bristle to move and enabling it to inscribe a visual medium. Initially, the phonautograph made recordings onto a lamp-blackened glass plate. A later version used a medium of lamp-blackened paper on a drum or cylinder—an arrangement to which Thomas Edison's later invention would bear striking resemblance. Other versions would draw a line representing the sound wave on to a roll of paper. The phonautograph was a laboratory curiosity for the study of acoustics. It was used to determine the vibrations per second for a musical pitch and to study sound and speech; it was not widely understood until after the development of the phonograph that the waveform recorded by the phonautograph was a record of the sound wavelength that needed only a playback mechanism to reproduce the sound.

Phonograph theory

Charles Cros, a French scientist, produced a theory (April 18, 1877) concerning a phonograph. Cros's work was only a theory, though and he did not manufacture a model.

The first phonograph

Patent drawing for Edison's phonograph, 05/18/1880. Thomas Alva Edison announced his invention of the first phonograph, a device for recording and replaying sound, on November 21, 1877 and he demonstrated the device for the first time on November 29 (he patented it on February 19, 1878; US Pat. No. 200,521). Edison's early phonographs recorded onto a phonograph cylinder using an up-down (vertical) motion of the stylus. Edison's early patents show that he also considered the idea that sound could be recorded as a spiral onto a disc, but Edison concentrated his efforts on cylinders, since the groove on the outside of a rotating cylinder provides a constant velocity to the stylus in the groove, which Edison considered more "scientifically correct". Edison's patent specified that the audio recording was embossed, and it was not until 1889 that engraved recordings were patented by Bell and Tainter. .....

British and American language usage differences

In British English "gramophone" came to refer to any sound reproducing machine using disc records, as disc records were popularized in the UK by the Gramophone Company. The term "phonograph" is usually restricted to devices playing cylinder records. In American English, "phonograph" was the most common generic term for any early sound reproducing machine. Berliner's Gramophone was considered a type of phonograph. "Gramophone" was a brand name, and as such in the same category as "Victrola," "Zon-o-phone," and "Graphonola" referring to specific brands of sound reproducing machines. The brand "Gramophone" was not used in the USA after 1901, and the word fell out of use there. In contemporary American usage "phonograph" most usually refers to disc record machines or turntables, the most common type of analogue recording from the 1910s on. The word has survived in America based on its nickname form, "Grammy", in the Grammy Awards. Strictly speaking, the gramophone is the machine reproducing sound from an engraved archive, whereas a phonograph is a machine that captures sound onto an engraved archive, i.e. a lathe.

Disc versus cylinder as a recording media

Disc recording is inherently neither better nor worse than cylinder recording in potential audio fidelity. Recordings made on a cylinder remain at a constant linear velocity for the entirety of the recording, while those made on a disc, have a higher linear velocity at the outer portion of the groove, compared to the inner portion. Edison's patented recording method recorded with vertical modulations in a groove, Berliner utilized a lateraly modulated groove. Though Edison's recording technology was better than Berliner's, there were commercial advantages to a disc system: Berliner successfully argued that his technology was different enough from Edison's that he did not need to pay royalties on it, which reduced his business expenses. Through experimentation, in 1892 Berliner began commercial production of his disc records, and "gramophones" or "talking-machines". His "gramophone record" was the first disc record to be offered to the public. They were five inches (12.7 cm) in diameter and recorded on one side only. Seven-inch (actual size: 17.5 cm) records followed in 1895. By 1901, ten-inch (actual size: 25.0 cm) records being sold by the Victor Talking Machine Company, and Berliner had sold his interests. By 1908, double sided disc recorded records became demanded by the public, and cylinders fell into disfavor. Edison felt the commercial pressure for disc records, and by 1912, though reluctant at first, his movement to disc records was in full swing. From the mid-1890s until the early 1920s both phonograph cylinder and disc recordings and machines to play them on were widely mass marketed and sold. The disc system gradually became more popular due to its cheaper price and better marketing by disc record companies. Edison ceased cylinder manufacture in the fall of 1929, and the history of disc and cylinder rivalry was concluded.

The dominance of the disc phonograph

Berliner's lateral disc record was the ancestor of the 78rpm, 45rpm, 33⅓rpm, and all other analogue disc records popular for use in sound recording through the 20th century. See gramophone record and vinyl record. Christmas 1925 brought improved radio technology and radio sales, bringing many phonograph dealers to financial ruin. With efforts at improved audio fidelity, the big record companies succeeded in keeping business booming through the end of the decade, but the record sales plummeted during the Great Depression, with many companies merging or going out of business. Booms in record sales returned after World War II. The "phonograph", "gramophone" or "turntable", remained a common element of home audio systems well after the introduction of other media such as audio tape and even the early years of the compact disc. They were not uncommon in home audio systems into the early 1990s.

Turntable technology

Drive systems: direct and belt

Most turntable designs use a either a belt drive or direct drive system. Earlier designs also used a rubberized idler wheel drive system. However, non-linear wear and decomposition of the wheel introduced noise and speed variations into the desired audio. These systems generally used a synchronous motor which ran at a speed synchronized to the AC frequency of the power supply. Different speeds were obtained by bringing differing diameter wheels into position against the bottom or inside edge of the platter. Belt drives brought improved motor and platter isolation compared to idler wheel designs. Motor noise heard as low frequency rumble was much reduced. It is difficult to design multiple speed synchronous motors, consequently DC servomotors with electronics providing speed control, have gained favour. On the most sophisticated designs, optical sensors on the platter are used to ensure the speed of the platter remains stable. Many platters have a continuous series of strobe markings machined around their edge to provide these pulses. A strobe effect can be observed by the operator to verify rotational speed. DC servomotors rotate in steps rather than continuously. This is referred to as cogging, and can add noise during playback. Helical armature motors can be used to overcome this. Modern high fidelity applications favor the use of belt-driven systems, as these isolate the revolving platter from motor-induced vibrations. Problems with material instability and deterioration have largely been solved by use of modern elastic polymers. Direct drive turntables, drive the platter directly, without utilizing intermediate wheels, belts, or gears as part of a drive train. The platter functions as a motor armature. This requires good engineering, with advanced electronics for acceleration and speed control. Matsushita's Technics division introduced the first commercially successful direct drive platter, model SP10, in 1969. The Technics SL-1200 turntable, introduced in 1972, was one of the most successful direct drive turntables ever produced. Its rapid acceleration up to speed, quartz locked speed control, electric braking system and its reliability made it a favourite with radio stations and disc jockeys right across the world. It was particularly popular with the disc jockeys who used it for beatmixing because it had a variable pitch control (first a knob and then a slider on the Mk 2), allowing variations of the rotational speed above and below the usual 33 and 45 RPM settings. The SL-1200 Mk2 turntable was still in production in the 1990s - a remarkable achievement in an increasingly digital world.

Pickup systems

cartridge Another major component is the pickup or cartridge. Early electronic phonographs used a piezo-electric quartz crystal for pickup, where the mechanical movement of the stylus in the groove generates a proportional electrical voltage. Crystal pickups are relatively robust, and yield a good level of signal which requires only a modest amount of amplification. A crystal's output tends not to be very linear, that is, it introduces unwanted distortion. It is difficult to make a crystal pickup suitable for stereo reproduction, as the stiff coupling between the crystal and the stylus prevents close tracking of the needle to the groove modulations. This tends to increase wear on the record, and introduces distortion. In all high-fidelity systems, the crystal pickup has been replaced by the magnetic cartridge using either a moving magnet or moving coil. In the moving magnet system, the stylus carries a tiny permanent magnet, which is positioned between a series of fixed coils. As the magnet vibrates in response to the stylus following the record groove, it induces a tiny current in the coils. This current, now a weak alternating current representing the original sound wave from the recording session, is fed to an amplifier which boosts the signal, and then to a loudspeaker where it is converted to sound waves. Because the magnet is so light, and is not coupled mechanically to the coils, the stylus follows the groove far more gently and faithfully. Moving coil systems, are generally more expensive and are preferred by some audiophiles. Here a tiny coil is attached to the stylus, and moves within the field of a permanent magnet. Magnetic cartridges provide a much lower output than a crystal pickup, in the range of a few millivolts, thus requiring a preamplifier stage. Moving-coil cartridges generate an even smaller signal, of a few hundred microvolts, and require additionally a transformer or pre-preamplifier stage. Electrical noise induced by power lines or other EMI are attenuated by various methods, including electromagnetic shielding in the signal cables connecting the pickup to the amplifier. The stylus is typically a conical diamond tip on an aluminum tubular cantilever for a monophonic sound or rugged use, and an elliptical diamond tip for a stereo or binaural signal. Some very expensive styli have ruby, boron, or carbon fiber cantilevers chosen for their exceptional stiffness. DJs use the more rugged conical (sometimes inaccurately called spherical) styli due to the frequent reversals of direction involved in scratching. Phonograph recordings are made with high frequencies boosted. Then during playback the high frequencies are rescaled to the initial level, which reduces groove background noise including clicks or pops. This is accomplished in the amplifier with a PHONO input that uses a standardized RIAA equalization curve.

Arm systems

adjustable counterweight Basic arm design has changed relatively little. S-Type tone-arms can be found on even the 1925 Victor Orthophonic phonograph. Originally, even though the tone-arm was light for earlier electric pickup, the full weight rested on the record. Right through to the crystal pickup, this was required to create sufficient tracking force to follow the grooves adequately with the relatively stiff styli. Naturally, record wear was not given much consideration. With the advent of the better technologies, including more powerful rare-earth magnetic cartridges, far lighter tracking forces became possible, and a balanced arm came into use. Many use a counterweight to offset the weight of the arm. The addition of a calibrated dial on the weight, provides for quick change of stylus pressure. Stylus pressure of 1 to 2 grams are currently the standard. Two types of tracking error incident to a standard arm can affect the sound. As the tone arm tracks the groove, the stylus drag tangent to the disc surface and resistance along the arm the combine to create a horizontal skating force towards the center of the disc. Modern arms provide a spring-loaded or hanging weight bias which offsets this force, so as to leave the net horizontal force near zero. The second error occurs as the arm sweeps in an arc across a disc recording, causing the angle between the cartridge head and groove direction to change slightly. A change in angle, albeit small, may have an audible effect by creating a differential force on the groove walls. Making the arm longer so as as to reduce this angle is one solution. Some arms have been manufactured with an auxillary arm which pivots the cartridge head on the main arm to maintain a constant angle. If the arm is not pivoted at a fixed point, but travels horizontally along a radius of the disc, there will be no skating force and no cartridge angle error. The arm is driven along a linear track using a servomechanism to position it properly. Matsushita's Technics division developed one such practical system with its model SL-10 turntable in 1979, ten years after the introduction of the first direct-drive turntable. Early Edison phonographs had utilized similar but spring powered drives to carry the stylus across the record at a pre-determined rate. In practice the linear tracking system is not widely used today due to its complexity and attendant expense. However some of the most sophisticated systems do employ this technique.

Front-loading systems

A brief mention could be made of one attempt to make the use of records more convenient, in the dawning age of the compact disc. In the early 1980s, one manufacturer designed an upright (front loading) record playing music centre, in which the record was placed in a door which hinged downwards to accept it. The door retracted automatically and the record was spun in the vertical plane. A pair of linear-tracking arms traversed the disk, one on each side, meaning that the whole record could be played without stopping and turning it over. The whole system was mechanically and electronically exceedingly complex, and while it worked, the system as a whole was aimed at the mass market and had only mediocre sound quality. The large physical size of the hinged door made it vulnerable to damage, and the retraction motor was barely able to lift its weight, especially after some years of use.

The phonograph in the 21st century

Phonographs or disc record turntables continue to be manufactured and sold into the 21st century, although in much smaller numbers. Conversely, the quality of the available record players, tonearms and cartridges has steadily improved since the 1990's. Many audiophiles prefer vinyl records played on record players to digital music sources such as CD or SACD, for their perceived better sound fidelity.
Image:TurntablesWWOZ.jpg
Phonograph turntables at a radio station, 2003
Updates to the 1970s era Technics SL-1200, have remained an industry standard for DJs to the present day. Turntables and vinyl records remain popular in mixing (mostly dance-oriented) forms of electronic music, where they allow great latitude for physical manipulation of the music by the DJ. In hip hop music, the turntable is used as a musical instrument. Manipulation of a record as part of the music rather than for normal playback or mixing, is called turntablism. The basis of turntablism and its most well known technique is scratching, pioneered by Grand Wizard Theodore. It was not until Herbie Hancock's Rockit in 1983 that the turntablism movement was recognized in popular music outside of a hip hop context. See list of turntablists for more influential turntablist artists. The laser turntable, which uses a laser as the pickup instead of a stylus in physical contact with the disk, was conceived of in the late 1980s, although early prototypes were not of usable audio quality. Practical laser turntables are now being manufactured by ELPJ. They are favoured by record libraries and some audiophiles since they eliminate wear completely. In fact, the turntable or record player is still the source of choice in high end audio systems. Experimentation is in progress in retrieving the audio from old records by scanning the disc and analysing the scanned image, rather than using any sort of turntable, by Ofer Springer at the Hebrew University of Jerusalem.

See also

category: audio engineering da:Fonograf de:Phonograph de:Grammofon es:fonógrafo he:פטיפון ja:蓄音機 nl:Fonograaf no:Grammofon pl:Fonograf pl:Gramofon sv:Grammofon

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